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  • Hey, Vsauce. Michael here.

  • And I'm with Destin in Alabama. What he's about to do is capture on a Phantom

  • camera at a 1080 frames a second a hawk - that one - catching a target.

  • But today we're going to talk about sound. First things first.

  • The Raptor Center takes care of raptors that have been injured, or would otherwise not

  • be able to survive in the wild on their own. For instance, this bald eagle named Spirit,

  • who was hit by a car that damaged his beak.

  • Okay, so that is the bald eagle.

  • Very interesting sound that it makes. But what I'm interested in today is the recording

  • of sound. It hasn't really been that long in human's

  • history that we've able to record sounds. In fact, it wasn't until 1859 with the invention

  • of the phonautograph in Paris that we first recorded sound.

  • It really blows your mind to listen to this. What you're about to hear is the very first

  • recording ever of any kind of sound.

  • One thing I found fascinating was that these

  • large birds have such high metabolisms that in order to figure out if they're hungry or

  • not all you have to do is weigh them. And if a bird weighs too much it means it's

  • not hungry and so they won't bring it out to fly, 'cause it might not come back.

  • It's not hungry, it's not gonna obey commands to get little bits of food.

  • But let's now time travel to 1860 and listen to the very earliest recording of the human

  • voice. What you're about to hear is the voice of

  • the inventor of the phonautograph signing a French folk song.

  • Three years after that recording Abraham Lincoln delivered The Gettysburg Address and three

  • hours before he gave the speech this photo was taken.

  • The only known photo of Lincoln at the historic event.

  • It dedicated a cemetery in Pennsylvania to the Battle of Gettysburg, the deadliest battle

  • of America Civil War, where more than 23,000 men died.

  • Now in attendance was a 9 year old boy named William V. Rathvon.

  • And in 1938, as he neared the end of his life, Rathvon took a copy of the speech and recorded

  • himself delivering it as he remembered Lincoln speaking it.

  • We don't have any audio of Lincoln delivering the speech, which makes this recording the

  • only one done by an eyewitness of the event. Pretty mind-blowing.

  • But what about sounds we don't wanna hear? For instance, fingernails scratching against

  • a blackboard. Well there are a lot of theories about why

  • that sound affects us so viscerally and so immediately.

  • Some of them argue that the sound of the scratching may mimic an early warning cry of early humans.

  • But more recent research suggests that it's actually certain frequencies inside that scratching

  • sound, specifically those between 2000 and 4000 Hz.

  • A range similar to the human voice. Our ear canals actually amplify those frequencies,

  • so that we can hear them better, but when it comes to the scratching of things on a

  • chalkboard, or styrofoam against styrofoam, those frequencies become too loud, making

  • it painful. Okay, now let's leave Earth and listen to

  • sounds from outer space. Now, I know what you're thinking, sound in

  • outer space is impossible. Sound waves need a medium to travel through

  • and in space you practically have a vacuum. I know.

  • But here's something really neat. The radio antenna on Voyager I was broadcasting

  • the signal back to Earth as Voyager passed through the rings of Saturn.

  • What you're about to listen to is that broadcast, and all the static and pings you hear are

  • actual pieces of Saturn's rings hitting the radio antenna.

  • But would outer space really be silent if I were to walk right out of a space craft

  • into it? I mean, I wouldn't survive very long, because

  • of a lack of air, a lack of air pressure, freezing temperatures, radiation, it would

  • be really terrible. But even though sound waves could not travel

  • through space itself, there is a medium that the sound can travel through.

  • My body. That's right.

  • As my blood boiled and my body inflated, it would vibrate my bones, it would vibrate my

  • body and in turn vibrate my ear drum, which is something that we experience every day

  • if you own a Justin Bieber singing toothbrush. Special toothbrushes like these vibrate in

  • a way that you can barely hear, but as soon as you bite down on it the vibrations go through

  • your jaw and jiggle your eardrum and you hear a quite high fidelity version of Justin Bieber's

  • "Baby" or "You Smile," which is fun. But what this really means is that in space

  • no one can hear you scream. But you can hear yourself inflate.

  • Okay, as you guys know, I'm in Alabama with Destin from SmarterEveryDay.

  • Now, even though I grew up in Kansas, I've never, in my entire life, fired a gun.

  • Well, Destin is a ballistics expert, he's one of the smartest guys I've ever met.

  • And tonight he's gonna let me fire a gun for the first time in my life.

  • This is a 9mm bullet, quite common. This is not gonna be the first thing I shoot

  • in my life. This is.

  • A 50 caliber bullet, Destin says it's a good idea, and that I'll be okay because I have

  • a beard.

  • And as always,

  • thanks for watching.

Hey, Vsauce. Michael here.

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B1 sound vibrate scratching hear lincoln recording

SOUNDS.

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    林宜悉 posted on 2020/03/28
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